University of Zurich researchers have developed Roboy, a four-foot-tall humanoid robot with a set of muscles inspired by the human musculoskeletal system. The plastic muscles work together via electrical motors and artificial tendons, enabling Roboy to mimic the flexible mechanics of biology, and could lead to a new class or robots that are lighter, safer, and able to move in a more natural way. “If you’re interested in more natural kinds of movements, tendon-driven technology needs to be explored,” says Zurich researcher Rolf Pfeifer. Robots designed to mimic human movement can help researchers explore how biomechanics can lead to more intelligent behavior. “I think [Roboy] can be a really interesting research platform for learning in systems with many degrees of freedom,” Pfeifer says. However, one of the biggest obstacles for tendon-driven engineers is finding a way to effectively model the human body’s complex motions. “The calibration of tendons is a challenge for [artificial intelligence] research,” says the Massachusetts Institute of Technology’s Sisir Karumanchi.